---
category: Date Time
created: '2021-04-10'
title: Get the total number of days in a year
updated: '2021-10-13'
---

**JavaScript version**

```js numberOfDays.js
const numberOfDays = (year) => ((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0 ? 366 : 365);

// Or
const numberOfDays = (year) => (new Date(year, 1, 29).getDate() === 29 ? 366 : 365);
```

**TypeScript version**

```ts numberOfDays.ts
const numberOfDays = (year: number): number => ((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0 ? 366 : 365);

// Or
const numberOfDays = (year: number): number => (new Date(year, 1, 29).getDate() === 29 ? 366 : 365);
```
